To prevent surface water and foreign objects from penetrating into a drilled well provided with a well casing, a closing cap is as a rule mounted over the upper end of the casing, said cap equipped with sleeves which extend upwards from the upper part of the cap and through which pass tubes or pipes from the pump that is immersed in the well opening. The pump is suspended in a wire or a chain, the upper end of which is secured in a loop which in turn is secured in a steel plate which is moulded into the upper part of the cap. The latter is made from rubber or other elastic material. Hose clamps are provided to tighten the sleeves sealingly about their associated tube and a hose clamp is likewise provided to tighten sealingly the downwardly projecting wall of the cap about the upper end of the well casing.
In general, well opening casings of two different dimensions are available on the market, viz. one well casing having an external diameter of 125 mm and one with an external diameter of 140 mm. Each casing dimension requires a closing cap of corresponding dimensions. For this reason, it has hitherto been necessary to stock closing caps of two different dimensions. The purpose of the subject invention is to remedy this drawback.